7z has an open architecture, so it can support any new compression method, too. The following
methods currently are integrated into 7z:
LZMA – Improved and optimized version of LZ77 algorithm
PPMD – Dmitry Shkarin’s PPMdH with small changes
BCJ – Converter for 32-bit x86 executables
BCJ2 – Converter for 32-bit x86 executables
BZip2 – Standard BWT algorithm
Deflate – Standard LZ77-based algorithm

LZMA is the default and general compression method of 7z format. The main features of LZMA are:
High compression ratio
Variable dictionary size (up to 4 GB)
Compression speed: about 1 MB/s on 2 GHz CPU
Decompression speed: about 10-20 MB/s on 2 GHz CPU
Small memory requirement for decompression (depend from dictionary size)
Small code size for decompression: about 5 KB
Supports multi-threading and P4’s hyper-threading

Whats New:
– The speed for LZMA/LZMA2 compressing was increased
by 8% for fastest/fast compression levels and
by 3% for normal/maximum compression levels.
– 7-Zip now shows Properties (Info) window and CRC/SHA results window
as “list view” window instead of “message box” window.
– Some improvements in zip, hfs and dmg code.
– Previous versions of 7-Zip could work incorrectly in “Large memory pages” mode in
Windows 10 because of some BUG with “Large Pages” in Windows 10.
Now 7-Zip doesn’t use “Large Pages” on Windows 10 up to revision 1709 (16299).
– Some bugs were fixed.